The ambiguous origin of thermochromism in molecular crystals of dichalcogenides: chalcogen conds versus dynamic Se−Se/Te−Te bonds
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Date
2023-11-06
Journal Title
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Publisher
Wiley
Abstract
We report thermochromism in crystals of diphenyl diselenide (dpdSe) and diphenyl ditelluride (dpdTe), which is at variance with the commonly known mechanisms of thermochromism in molecular crystals. Variable temperature neutron diffraction studies indicated no conformational change, tautomerization or phase transition between 100 K and 295 K. High‐pressure crystallography studies indicated no associated piezochromism in dpdSe and dpdTe crystals. The evolution of the crystal structures and their electronic band structure with pressure and temperature reveal the contributions of intramolecular and intermolecular factors towards the origin of thermochromism—especially the intermolecular Se⋅⋅⋅Se and Te⋅⋅⋅Te chalcogen bonds and torsional modes of vibrations around the dynamic Se−Se and Te−Te bonds. Further, a co‐crystal of dpdSe with iodine (dpdSe‐I2) and an alloy crystal of dpdSe and dpdTe implied a predominantly intramolecular origin of the observed thermochromism associated with vibronic coupling. © 1999-2024 John Wiley & Sons
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Keywords
Thermochromatography, Crystals, Neutron diffraction, Phase transformations, Crystallography, Temperature range, Pressure range, Intermolecular forces, Coupling
Citation
Thomas, S. P., Singh, A., Grosjean, A., Alhameedi, K., Grønbech, T. B. E., Piltz, R., Edwards, A. J., & Iversen, B. B. (2023). The ambiguous origin of thermochromism in molecular crystals of dichalcogenides: chalcogen conds versus dynamic Se−Se/Te−Te bonds. Angewandte Chemie International Edition, 62(45), e202311044. doi:10.1002/anie.202311044